Hydrocracking catalyst and a diesel production process

ABSTRACT

The invention provides an amorphous hydrocracking catalyst for conversion of a hydrocarbon feed having a fraction above the diesel boiling range to diesel and a process using said catalyst. The catalyst includes Al 2 0 3 —SiO 2  support, a noble catalytically active metal which is active for hydrocracking of a hydrocarbon above the diesel boiling range and a transition metal oxide selected from group V, VI and VII.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/ZA01/00064, filed May 24, 2001, which claims priority to SouthAfrican Application No. 2000/2594, filed May 25, 2000, South AfricanApplication No. 2000/2595, filed May 25, 2000, U.S. ProvisionalApplication No. 60/207,121, filed May 25, 2000, and U.S. ProvisionalApplication No. 60/207,635, filed May 25, 2000. The contents of theprior applications are incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

The invention relates to a hydrocracking catalyst suitable for theproduction of diesel boiling range hydrocarbons and to a dieselproduction process using said catalyst.

BACKGROUND TO THE INVENTION

The applicant is aware that presently in order to produce diesel from ahydrocarbon feed including a fraction having a boiling point in excessof the diesel boiling range by hydrocracking a high recirculation ratiois required thereby leading to reduced viability of the production ofsaid diesel. The high recirculation ratio is necessitated, for amongstother reasons, by the relatively low conversions and yields to thedesired products

The applicant is further aware that diesel for commercial use shouldpreferably have good cold flow properties, a low cloud point, and acetane number in excess of 40.

The applicant is also aware that existing hydrocracking catalysts usedpresently for the production of diesel from a hydrocarbon feed having afraction having a boiling point above the diesel boiling range includecommercially available amorphous Ni/W/Al₂O₃SiO₂ catalysts as well asNi/Mo/Al₂O₃SiO₂ catalysts which require a high recirculation ratio asdescribed above and amorphous Pt/Al₂O₃SiO₂ which is a hydrocracking anddewaxing catalyst which also requires a high recirculation ratio asdescribed above in order to produce said diesel.

The applicant is also aware of an article by S Rajagopal, J. A. Marzariand R Miranda entitled Silica-Alumina-Supported Mo Oxide Catalysts:“Genesis and Demise of Brönsted-Lewis Acidity”, which article waspublished in the Journal of Catalysis 151, 192-203 (1995). The entirearticle is incorporated in this specification by reference as ifspecifically reproduced here.

In the aforementioned article the authors summarise that the ratio ofBrönsted to Lewis acid sites concentration (B/L) increases with SiO₂content in the support and reaches a maximum for SiO₂:Al₂O₃ of 3:1 byweight. For alumina rich supports B/L increases continuously with MoO₃loading because of the generation of new Brönsted acid sites anddecrease of Lewis acid sites, up to a theoretical maximum of 12 wt %MoO₃. The article does not propose the manufacture of a catalyst of thetype of this invention nor would the results set out in the article leada man skilled in the art to conclude that a catalyst in accordance withthis invention could be manufactured.

In this specification, unless the context clearly indicates to thecontrary, the term conversion is used to indicate the conversion of thehydrocarbon feed to reaction products on a single pass through thereactor i.e. without recycle of reactor bottoms.

Thus, after prolonged and laborious experimentation and development workon diesel production the applicant now proposes a new catalyst and a newdiesel production process in accordance with the invention.

SUMMARY OF THE INVENTION

The invention provides an amorphous hydrocracking catalyst forconversion of at least a portion of a hydrocarbon feed having a fractionabove the diesel boiling range to diesel, said catalyst including:

-   -   a Al₂O₃—SiO₂ support;    -   a noble catalytically active metal which is active at least for        the hydrocracking of a hydrocarbon above the diesel boiling        range; and    -   a transition metal oxide wherein the transition metal is        selected from Group V, Group VI and Group VII transition metals.

The ratio of SiO₂ to Al₂O₃ in the support may be between 1:4 and 4:1.

The ratio of SiO₂ to Al₂O₃ in the support may be between 1:2 and 7:2.

The ratio of SiO₂ to Al₂O₃ in the support may be between 2:4 and 7:2.

The ratio of SiO₂ to Al₂O₃ in the support may be about 3:1.

The catalytically active noble metal may be Pt, Pd, Ir, or Rh.

The catalytically active noble metal is typically Pt.

The catalytically active noble metal may be present at between 0.1% to5% of the weight of the catalyst.

The catalytically active noble metal is typically present at between0.5% to 1.5% of the weight of the catalyst.

The catalytically active noble metal is usually about 1.2% of the weightof the catalyst.

The transition metal oxide is typically a Group Vi transition metaloxide, for example, MoO₃.

The transition metal oxide may be between about 0.5% and 15% of thecatalyst weight.

The transition metal oxide may be between about 1.5% and 12% of thecatalyst weight.

Typically the transition metal oxide is about 2% of the catalyst weight.

In one embodiment the catalyst is Pt/MoO₃/Al₂O₃SiO₂ having about 1.2 wt% Pt and about 2 wt % MoO₃, and a SiO₂ to Al₂O₃ weight ratio of about3:1.

The catalyst is a non-sulphided catalyst.

According to a further aspect of the invention there is provided anamorphous hydrocracking catalyst for conversion of at least a portion ofa hydrocarbon feed having a fraction above the diesel boiling range todiesel, said catalyst having an acidity of between 0.1 and 0.9 mmolNH₃/g catalyst.

Typically, said catalyst has an acidity of between 0.25 and 0.6 mmolNH₃/g catalyst.

Typically, said catalyst has an acidity when freshly prepared of 0.38mmol NH₃/g catalyst

Typically, said catalyst has an acidity when used (spent) of 0.45 mmolNH₃/g catalyst

The catalyst may have a Brönsted/Lewis ratio (B/L) of between 0.3 and1.2.

Typically, said catalyst may have a Brönsted/Lewis ratio of 0.44.

The applicant believes that the B/L ratio of the support of thecatalyst, which is substantially higher than some prior arthydrocracking catalysts, results in the catalyst of the inventionfavouring a tertiary to tertiary cracking mechanism, also called a TypeA cracking mechanism, which cracking mechanism is substantially fasterthan the Type B1 and B2 cracking mechanisms.

It is believed that a high B/L content on the amorphous support isimportant as the alkene receives a proton from the support, thentransforms into a carbocaton.

Isomerization is an important step in the hydrocracking mechanism as alinear paraffin molecule has typically to be isomerized three timesbefore the dominant A-type hydrocracking takes place.

Over bifunctional catalysts, it has been found that type A hydrocrackingis by far the fastest reaction; 375 times faster than type B1 and 1050times faster than type B2 hydrocracking

The applicant further believes that the non-sulphided nature of thecatalyst of the invention is advantageous in a hydrocarbon processingstream where sulphur levels are very low or absent, such as aFischer-Tropsch process in which there is typically no or little sulphurin the feedstream and thus sulphur removal is not provided for.

According to a further aspect of the invention there is provided aprocess for conversion of at least a portion of a hydrocarbon feedhaving a component above the diesel boiling range to diesel, saidprocess including contacting under conversion temperatures and pressuressaid hydrocarbon feed with a catalyst including:

-   -   a Al₂O₃SiO₂ support;    -   a noble catalytically active metal which is active at least for        the hydrocracking of a hydrocarbon above the diesel boiling        range; and    -   a transition metal oxide wherein the transition metal is        selected from Group V, Group VI and Group VII transition metals.

The ratio of SiO₂ to Al₂O₃ in the support may be between 1:4 and 4:1.

The ratio of SiO₂ to Al₂O₃ in the support may be between 1:2 and 7:2.

The ratio of SiO₂ to Al₂O₃ in the support may be between 2:4 and 7:2.

The ratio of SiO₂ to Al₂O₃ in the support may be about 3:1.

The catalytically active noble metal may be Pt, Pd. Ir, or Rh.

The catalytically active noble metal is typically Pt.

The catalytically active noble metal may be present at between 0.1% to5% of the weight of the catalyst.

The catalytically active noble metal is typically present at between0.5% to 1.5% of the weight of the catalyst.

The catalytically active noble metal is usually about 1.2% of the weightof the catalyst.

The transition metal oxide may be any Group VI b (Group 6) oxide,typically MoO₃

The transition metal oxide may be between about 0.5% and 15% of thecatalyst weight.

The transition metal oxide may be between about 1.5% and 12% of thecatalyst weight.

Typically the transition metal oxide is about 2% of the catalyst weight.

In one embodiment the catalyst is Pt/MoO₃/Al₂O₃SiO₂ having about 1.2 wt% Pt and about 2 wt % MoO₃, and an SiO₂ to Al₂O₃ weight ratio of about3:1.

The catalyst is a non-sulphided catalyst.

The process may be carried out at a temperature of between 250° C. and450° C.

The process may be carried out at a temperature of between 330° C. and390° C.

The process may be carried out at temperature of between about 350° C.and 380° C.

Typically the process is carried out at between 360° C. to 370°, usually370° C.

The process may be carried out a pressure of between 10 and 200 Bar,although a typical range is between 15 and 70 Bar.

The process may be carried out at 70 Bar where a high diesel to naphtharatio of above 6 is required at a conversion rate of above 60%.

The process may be carried out at a pressure of about 70 Bar and at atemperature of about 370° C. to give a diesel to naphtha ratio of about6.4 at a conversion of about 70%, said diesel having a cloud point ofabout −19° C.

The process may be carried out without recycle of a bottoms fraction.

The process may be carried out with a recycle ratio of bottoms fractionfrom the reactor to fresh hydrocarbon feed of from 4:1 to 1:9 (20%/-90%conversion)

The process may be carried out with a volumetric H₂ to hydrocarbon feedratio of between 800:1 and 3000:1, typically 1000:1 to 1500:1.

The process may be carried out with a weight hourly space velocity(whsv) of between 0.25 h⁻¹ and 1.5 h⁻¹, typically 0.5 h ⁻¹ and 1 h⁻¹.

The diesel and naphtha products of the process may be produced at aratio of at least 6:1, typically 6.4:1.

The conversion to diesel may be at least 60%, typically 70% and even ashigh as 80%.

In one embodiment, the diesel to naphtha ratio is about 6.4:1 at aconversion to diesel of 70% when the process is carried out at 370° C.and a pressure of 70 Bar.

Typically the hydrocarbon feed is predominantly a wax feed, for examplea Fischer-Tropsch wax.

According to yet a further aspect of the invention, there is provided aprocess for conversion of at least a portion of a hydrocarbon feedhaving a component above the diesel boiling range to diesel, saidprocess including contacting under conversion temperatures and pressuressaid hydrocarbon feed with a conversion catalyst, wherein productfractions of the process include:

-   -   a naphtha fraction;    -   a diesel fraction; and    -   a bottoms fraction which predominantly contains hydrocarbons        having a boiling range above the diesel boiling range;        wherein the diesel to naphtha ratio is at least 6 when the        conversion of hydrocarbon feed is at least 60%.

The diesel to naphtha ratio may be between 6 and 7, typically 6.4 at aconversion of 70% when the process is carried out at 370° C. and at apressure of 70 Bar.

The process may include the recycling of the bottoms fraction whereinthe recycle ratio of bottoms fraction to fresh hydrocarbon feed is lessthan 4:1, typically less than 3:7.

In one embodiment there is no recycling of the bottoms fraction.

The conversion catalyst may include:

-   -   a Al₂O₃—SiO₂ support;    -   a noble catalytically active metal which is active at least for        the hydrocracking of a hydrocarbon above the diesel boiling        range; and    -   a transition metal oxide wherein the transition metal is        selected from Group V, Group VI and Group VII transition metals.

The ratio of SiO₂ to Al₂O₃ in the support may be between 1:4 and 4:1.

The ratio of SiO₂ to Al₂O₃ in the support may be between 1:2 and 7:2.

The ratio of SiO₂ to Al₂O₃ in the support may be between 2:4 and 7:2.

The ratio of SiO₂ to Al₂O₃ in the support may be about 3:1.

The catalytically active noble metal may be Pt, Pd, Ir, or Rh.

The catalytically active noble metal is typically Pt.

The catalytically active noble metal may be present at between 0.1% to5% of the weight of the catalyst.

The catalytically active noble metal is typically present at between0.5% to 1.5% of the weight of the catalyst.

The catalytically active noble metal is usually about 1.2% of the weightof the catalyst.

The transition metal oxide may be any Group 6 oxide, typically MoO₃.

The transition metal oxide may be between about 0.5% and 15% of thecatalyst weight.

The transition metal oxide may be between about 1.5% and 12% of thecatalyst weight.

Typically the transition metal oxide is about 2% of the catalyst weight.

In one embodiment the catalyst is Pt/MoO₃/Al₂O₃SiO₂ having about 1.2 wt% Pt and about 2 wt % MoO₃, and a SiO₂ to Al₂O₃ weight ratio of about3:1.

The catalyst is a non-sulphided catalyst.

The process may be carried out at a temperature of between 250° C. and450° C.

The process may be carried out at a temperature of between 330° C. and390° C.

The process may be carried out at temperature of between about 350° C.and 380° C.

Typically the process is carried out at between 360° C. to 370°, usually370° C.

The process may be carried out a pressure of between 10 and 200 Bar,although a typical range is between 15 and 70 Bar.

The process may be carried out at 70 Bar where a high diesel to naphtharatio of above 6 is required at a conversion rate of above 60%.

The process may be carried out at a pressure of about 70 Bar and at atemperature of about 370° C. to give a diesel to naphtha ratio of about6.4 at a conversion of about 70%, said diesel having a cloud point ofabout −19° C.

The process may be carried out with a volumetric H₂ to hydrocarbon feedratio of between 800:1 and 3000:1, typically 1000:1 to 1500:1.

The process may be carried out with a weight hourly space velocity(whsv) of between 0.25 h⁻¹ and 1.5 h⁻¹, typically 0.5 h⁻¹ and 1 h⁻¹.

The conversion to diesel may be at least 60%, typically 70% and even ashigh as 80%.

Typically the hydrocarbon feed is predominantly a wax feed, for examplea Fischer-Tropsch wax.

The Fischer-Tropsch wax may be selected from a Group including

-   -   a primary FT reactor product;    -   wax A, or distillation fractions thereof;    -   wax B;    -   wax C        wherein waxes A, B and C have characteristics as set out in the        table below.        Wax Characteristics:

Wax Type Congealing point (° C.) Substantial carbon distribution A83-103, typically 93  C₅-C₁₂₀ B  49-69, typically 59 C₁₇-C₄₅ C  71-91,typically 81 C₃₀-C₈₅

The invention extends to a diesel produced by the process of theinvention, the diesel having a cetane number in excess of 40.

The diesel may have a cetane number between 65 and 75, typically 70.

The diesel may have a cloud point below −19° C.

Typically the diesel has a cloud point below −25° C.

SPECIFIC DESCRIPTION OF THE INVENTION CATALYST EXAMPLE 1

A non-sulphided Pt/MoO₃/Al₂O₃—SiO₂ catalyst was prepared in which thesupport was amorphous. The particle size of the catalyst was ⅛″.

Catalyst Preparation.

75% Degussa silica (300 grams), 25% Degussa alumina (100 grams) and HNO₃55% (100 ml) were introduced into a mixer. While mixing, distilled waterwas added drop wise until a stiff dough was obtained. The paste waskneaded for about 3 hours.

At the end of the reaction, the mixture was placed in an oven at 120° C.for 10 hours in order to ensure proper drying, then pelletised to 3000and 6000 micrometers.

Following this, the support was calcined in air at 550° C. for 3 hours.

100 grams of the support was impregnated with 100 ml of(NH₄)₆Mo₇O₂₄.4H₂O (2.4525 grams) solution until a 2.2% MoO₃ content wasloaded. The mixture was calcined in air at 400° C. for 4 hours. Then 100grams of the mixture was impregnated with 100 ml of [Pt(NH₃)₄](NO₃)₂(1.9846 grams) solution until a 1.2% Pt content was loaded; then thecatalyst was calcined at 400° C. in air for 4 hours in order toeliminate all the NH₃ and to obtain the desired oxide MoO₃.

Reduction of the Catalyst

The catalyst was reduced in-situ in a fixed bed at 350° C. for 8 hourswith a hydrogen flow rate of 1.7 l/min in order to reduce the platinum.

Catalyst Testing Apparatus

The catalyst testing was carried out in a fixed bed reactor operating indown flow mode.

Other Apparatus and Techniques Used for Catalyst Characterization

BET Surface Area Measurements and Data

A Gemini micromeritics surface area machine was used. BET data of thecatalyst was obtained. Catalyst characteristics are summarized in tableA below.

TABLE A Catalyst Characteristics A B C D E F G H Pt/MoO₃/Al₂O₃—SiO₂ 1.2%Pt 65.1% SiO₂ 233 0.55 0.38 100 0.44 2.2% MoO₃ 19% Al₂O₃ A: catalystwith particle size: ⅛″. B: active agents. C: carrier D: BET surface area(m²/g) E: total pore volume (cm³/g) F: acid sites (mmol NH₃/g cat) G:average pore diameter (Angström) H: Brönsted/Lewis (B/L)

Inductive Couple Plasma (ICP)

The amorphous support (Al₂O₃—SiO₂) was impregnated with a metal oxide(MoO₃) and a noble metal (Pt) and metal loadings were ascertained bymeans of ICP.

The analyses were performed by AARL. ICP data for Pt/MoO₃/Al₂O₃—SiO₂ wasobtained. The results are given in table B below.

TABLE B Percentage of metal loading on the Al₂O₃—SiO₃ Percentage ofMetal loading Sample % added % found Pt/MoO₃/Al₂O₃—SiO₂ 1.3% Pt/ 1.2%Pt/ 2.3% MoO₃ 2.2% MoO₃

X-Ray Diffraction (XRD)

A Siemens D500 X-ray Powder Diffractometer was used to determine thecrystallinity of the catalyst and the catalyst was found to beclassifiable as amorphous.

Temperature Program Reduction (TPR)

A Micromeritics TPR 2900 analyzer was used. The catalyst was reduced at350° C.

Temperature Program Desorption (TPD)

A Micromeritics TPD 2900 NH₃analyzer was used for the determination ofthe catalyst acidity.

Catalyst Use

Tests to convert a Fischer-Tropsch reaction product wax to diesel andnaphtha using the catalyst described above were performed at 370° C. ina fixed bed reactor without recycle.

Tests were also conducted to convert a Fischer-Tropsch reaction productto diesel and naphtha using the prior art Ni-W or Ni-Mo catalysts at370° C. in a fixed bed reactor without recycle.

The results showed that the catalyst of the invention gave superiorresults of a diesel to naphtha ratio of 6.4:1 and a conversion (C₂₃₊converted in product) of 70%, the diesel having an acceptable cloudpoint of about −19° C.

The catalyst was also found not to have decreased in activity orperformance after 190 days of constant use whereas the prior artcatalysts are known to have a gradual decrease in activity from thefirst day of use until the catalyst must be replaced.

PROCESS EXAMPLE 1

An amorphous catalyst having the properties as set out in tables 1 and 2below and originally designed for the conversion of waxes to lube oilswas prepared and used in a hydrocracking process to convert aFischer-Tropsch wax C to diesel. Wax C has a congealing point of 81° C.and a substantial carbon distribution of C₃₀ to C₈₅, as shown in thetable above.

TABLE 1 Catalyst Characteristics A B C D E F G H Pt/MoO₃/Al₂O₃— 1.2% Pt65.1% SiO₂ 219 0.55 0.38 100 0.44 SiO₂ 2.2% MoO₃ 19% Al₂O₃ A: catalystwith particle size: ⅛″ and catalyst bulk density between 0.2 and 2.5 B:active agents. C: carrier D: BET surface area (m²/g) E: total porevolume (cm³/g) F: acid sites (mmol NH₃/g cat) G: average pore diameter,Angström (Å) H: Brönsted/Lewis (B/L)

TABLE 2 Percentage of metal loading on the Al₂O₃—SiO₃ Percentage ofMetal loaded Sample % added % found Pt/MoO₃/Al₂O₃—SiO₂ 1.3% Pt/ 1.2% Pt/2.3% MoO₃ 2.2% MoO₃

Temperature Program Reduction (TPR)

A Micromeritics TPR 2900 analyzer was used. The catalyst was reduced at350° C.

Temperature Program Desorption (TPD)

A Micromeritics TPD 2900 NH₃ analyser was used for the determination ofthe catalyst acidity.

Gas Chromatography (GC)

A GC was used to identify and to determine the carbon numberdistribution of the products. The analyses were performed byInstrumental Techniques laboratory.

Nuclear Magnetic Resonance (NMR)

A Varian Unity Inova 400 mHz NMR was used to determine the cetane numberof the diesel fraction.

Catalyst Use

Tests to convert a Fischer-Tropsch wax having a liquid point of 80° C.(wax C) to diesel were performed under a variety of conditions. Thetests were conducted at pressures of 35 bar, 50 bar and 70 bar.

A summary of reactions performed is given in tables 3, 4 and 5.

Reactions were also performed with hydrocracked bottoms (HB) “>370° C.”from wax C (HB) as feedstock. A summary of the experiments performedusing HB as feedstock is shown in table 6.

The diesel fraction produced 170°-370° C. during the experiments werefractionated according to the true boiling point (TBP) while thespecification requires a diesel cut 170°-370° C. according to the ASTMD-86.

The diesel fraction of 170°-370° C. in TBP corresponds almost to190°-390° C. in ASTM-D86; therefore all flash points values resultedfrom the test runs were too high as the initial boiling point of thediesel were shifted by almost 20° C.

Wax C Conversion Over Pt/MoO₃/Al₂O₃—SiO₂ Catalyst

Wax C at a flow rate of 0.9-1.9 ml/min and H₂ at a flow rate of 1.4-2.6Nl/min were passed through Pt/MoO₃/Al₂O₃—SiO₂ catalyst (96.2 g) in thereactor.

Separate runs were carded out at various pressures (35 bar, 50 bar and70 bar) and various temperatures (360° C., 365° C. and 370° C.).

The results obtained after 3-4 days run at each temperature and pressureare shown in tables 3, 4 and 5.

TABLE 3 The effect of temperature on diesel selectivity and dieselproperties at 50 bar, whsv of 0.5 h⁻¹ and H₂/wax of 1400. RunSpecifications R 08 R 09 R 10 Pressure (bar) 50 50 50 Temperature 370365 360 (° C.) Whsv (h⁻¹) 0.5 0.5 0.5 H₂:wax 1432 1427 1467Conversion_(D) (%) 84.4 78.9 58 S_(C1-C4) (%) 4.3 4.5 2.3 S_(C5-C9) (%)21.5 20.7 16.4 S_(C10-C22) (%) 74.2 74.8 81.3 Y_(C1-C4) (%) 3.6 3.6 1.3Y_(C5-C9) (%) 18.1 16.3 9.5 Y_(C10-C22) (%) 62.6 59 47.2 Residue (%)15.6 21.1 42 Diesel/naphtha 3.5 3.6 5 Diesel Properties iP/nP in C₁₀-C₂₂7.7 6.4 7.3 Cloud point (° C.) (−19° C.) max −25 −9 −3 Flash point (°C.) 57 min 84 84 78 Viscosity @ 2.0 < cSt < 5.3 2.6 2.7 3.2 40° C.Density @ 20° C. 0.766 g/cm³ 0.775 0.777 0.781 Cetane number 70 min 7172 73 Conversion_(D) (%) = (C₂₃₊ in fresh feed − C₂₃₊ in product)/C₂₃₊in fresh feed * 100 from Carbon Number Distribution (CND) S_(C10-C22)(%) = Diesel selectivity calculated as: (C₁₀-C₂₂ in product − C₁₀-C₂₂ infresh feed)/(C₁-C₂₂ in product − C₁-C₂₂ in fresh feed) * 100 Y_(C10-C22)(%) = Diesel yield calculated as: conversion_(D) * S_(C10-C22)

Conversion of Wax C at 50 Bar

As regards the quality of the products, the diesel fraction (C₁₀₋₂₂)produced presents excellent properties. An average ratio iC₁₀₋₂₂/nC₁₀₋₂₂of 7/1 has been obtained. This high ratio explains the cloud point of−25° C. A diesel cetane number of 71 was found.

TABLE 4 Effect of temperature on diesel selectivity and dieselproperties at 35 bar, whsv of 0.5 h⁻¹ and H₂/wax of 1400 Run R 11 R 12 R13 Catalyst Pt/Mo/Al—Si Pt/Mo/Al—Si Pt/Mo/Al—Si Pressure (bar) 35 35 35Temperature (° C.) 360 365 370 Whsv (h⁻¹) 0.5 0.5 0.5 H₂:wax 1353 14521507 Conversion_(D) (%) 72.8 85.5 95.2 Y_(C1-C4) (%) 1.0 3.7 2.0Y_(C5-C9) (%) 14.6 19.7 29.3 Y_(C10-C22) (%) 57.3 62.2 64.0 Residue (%)27.1 14.4 4.7 Diesel/naphtha 3.9 3.2 2.2 Diesel Properties iP/Np inC₁₀-C₂₂ 4.8 7.9 6 Cloud point (° C.) −29 −34 −39 CFPP (° C.) −34 −39<−39 Flash point (° C.) 88 80 75 Viscosity @ 40° C. 2.5 2.7 2.2 Density@ 20° C. 0.776 0.777 0.771 Cetane number 72 73 69

Conversion of Wax C at 370° C.

From table 5 the following points may be observed:

It was found that by lowering the pressure from 70 bar to 35 bar the

-   -   conversion increases    -   cold properties improve i.e. cloud point at 70 bar was −6° C.        decreasing to −39° C. at 35 bar as can be seen from table 5.

The Cetane number, which measures the ignition quality of a diesel fuel,remained high and almost unchanged at low pressure. This can beexplained by the insignificant aromatic content in the diesel (below1%).

TABLE 5 The effect of pressure on diesel selectivity and dieselproperties at 370° C., whsv of 0.5 h⁻¹ and H₂/wax of 1400. Run R 07 R 08R 13 Pressure (bar) 70 50 35 Temperature (° C.) 370 370 370 Whsv (h⁻¹)0.5 0.5 0.5 H₂:wax 1327 1432 1507 Conversion_(D) (%) 48.7 84.4 95.2Y_(C1-C4) (%) 2.6 3.6 2.0 Y_(C5-C9) (%) 8.2 18.1 29.3 Y_(C10-C22) (%)37.8 62.6 64.0 Residue (%) 51.3 15.6 4.7 Diesel/naphtha 4.6 3.5 2.2Diesel Properties iP/nP in C₁₀-C₂₂ 4.6 7.7 6 Cloud point (° C.) −6 −25−39 CFPP (° C.) <−39 Flash point (° C.) 86 84 75 Viscosity @ 40° C. 2.72.6 2.2 Density @ 20° C. 0.777 0.775 0.771 Cetane number 72 71 69

Conversion of Hydrocracked Bottoms (“>370° C.”) over aPt/MoO₃/Al₂O₃—SiO₂ Catalyst.

A study was also undertaken in which hydrocracked bottoms (HB, “>370°C.”) from wax C was used as feedstock. The purpose of this was to assessthe product yielded and its quality.

Feed at a rate of 0.9-1.9 ml/min and H₂ at a flow rate of 1.4-2.6 Nl/minwere passed through a Pt/MoO₃/Al₂O₃—SiO₂ catalyst (96.2 g) bed in thereactor.

Reactions were performed at two different temperatures, keeping otherparameters constant. The results of the runs carried out at temperaturesof 350° C. and 340° C., a pressure of 35 bar, a whsv of 0.5 h⁻¹ and aH₂/wax of 1200 are shown in table 6.

TABLE 6 The effect of the hydrocracked Wax C bottoms (material >370° C.)on diesel selectivity and diesel properties. Run R 15 R 16 Pressure(bar) 35 35 Temperature (° C.) 350 340 Whsv (h⁻¹) 0.53 0.55 H₂:wax 12151209 Conversion_(D) (%) 93.7 54.8 Y_(C1-C4) (%) 2.7 1.1 Y_(C5-C9) (%)15.6 9.2 Y_(C10-C22) (%) 75.5 44.5 Residue (%) 6.3 45.3 Diesel/naphtha 55 Diesel Properties iP/nP in C₁₀-C₂₂ 7.8 6.2 Cloud point (° C.) −21 −28CFPP (° C.) −38 Flash point (° C.) 89 97 Viscosity @ 40° C. 2.75 3.16Density @ 20° C. 0.775 0.802 Cetane number 70 72

Conversion of Hydrocracked Bottoms Wax C (bp>370° C.) Using the Pt/MoSilica-Alumina Catalyst

The reactor temperature was set to 350° C. and was then reduced to 340°C. to avoid an overcracking of the hydrocracked wax C feedstock as itcontains significant amount of iso-paraffins.

It can be noticed that at a conversion of 93.7% as well as 54.8%excellent cold properties have been obtained in both runs (−21° C. &−28° C.) combined with high cetane number (70 & 72). The effect ofconversion on cloud point was out of correlation i.e. at 93.7%conversion, it is expected a cloud point much lower than at 54.8%conversion. The explanation could be that molecular rearrangements inthe iso-paraffins structures might happen. Overcracking of the highlybranched iso-paraffins might affect the diesel cold properties.

PROCESS EXAMPLE 2

An amorphous catalyst having the properties as set out in tables 1 and 2of Process Example 1 was prepared and used in a hydrocracking process toconvert a Fischer-Tropsch wax known as Wax A to diesel. Wax A has acongealing point of 91° C. and a substantial carbon distribution of C₅to C₁₂₀.

The amorphous non-sulphided, Pt/MoO₃/Al₂O₃—SiO₂ was used to hydrocrackWax A with the objective to evaluate the catalyst for hydroisomerisationof waxes to lube base oils.

Surprisingly, the catalyst showed a good activity and a good selectivitytowards diesel. The activity of the catalyst was further tested usingthe full range Fischer-Tropsch wax as feedstock.

Catalyst Use

Reactions to convert Wax A to diesel were performed under a variety ofconditions. A pressure range of 35 bar, 50 bar and 70 bar, a temperaturerange of 365° C., 370° C. and 380° C., a weight hourly space velocity(whsv) of 0.5 h⁻¹, and a H₂/wax range of 1000, 1200 and 1300 werecovered in the study.

A summary of reactions performed is given in table 7.

Typical experimental details are given below.

Wax a Conversion Using the Pt/MoO₃/Al₂O₃—SiO₂ Catalyst

Wax A at a flow rate of 0.9-1.9 ml/min and H₂ at a flow rate of 1.4-2.6Nl/min was passed through Pt/MoO₃/Al₂O₃—SiO₂ catalyst (96.2 g) in thereactor.

TABLE 7 The effect of temperature on diesel selectivity and dieselproperties at 70 bar and whsv of 0.5 h⁻¹ Run R 27 R 28 Pressure (bar) 7070 Temperature © 370 380 WHSV (h⁻¹) 0.5 0.5 H₂:wax 1221 1242 Conversion(%) 70.1 79.5 Y_(C1-C4) (%) 1.2 1.3 Y_(C5-C9) (%) 9.3 18.8 Y_(C10-C22)(%) 59.6 59.4 Residue (%) 29.9 20.5 Diesel/naphtha 6.4 3.2 DieselProperties iP/nP in C₁₀-C₂₂ 3.9 4.1 Cloud point (° C.) −19 −20 Cetanenumber 70 69

PROCESS EXAMPLE 3

An amorphous non-sulphided catalyst having the properties as set out intables 1 and 2 of Example 1, Pt/MoO₃/Al₂O₃—SiO₂, was used to convert WaxB with the objective to evaluate the catalyst for hydroisomerisation ofwaxes to lube base oils. Surprisingly the catalyst showed a goodactivity and a good selectivity towards diesel. Wax B has a congealingpoint of 59° C. and a substantial carbon distribution of C₁₇ to C₄₅.

It was found, to the surprise of the applicant, that the preparedPt/MoO₃/Al₂O₃—SiO₂ catalyst produces an excellent diesel comparable tothe diesel quality obtained by hydrocracking Fischer-Tropsch (FT) waxesusing other commercially available amorphous hydrocracking catalysts.

Catalyst Use

Wax B was converted to diesel under a variety of conditions. A pressurerange of 15 bar, 35 bar, 50 bar and 70 bar, a temperature range of 350°C. to 380° C., a weight hourly space velocity (whsv) range of 0.5 h⁻¹and a H₂/wax range of 1000, 1200 and 3000 were tested with the abovecatalyst and the reactions performed are given in table 8.

The test work was performed in a bench scale fixed bed reactor.

Wax B Conversion Over Pt/MoO₃/Al₂O₃—SiO₂

Wax B at a flow rate of 0.054-0.114 l/h, H₂ at a flow rate of 84-156Nl/h was passed over the Pt/MoO₃/Al₂O₃—SiO₂ catalyst (96.2 g) in thereactor.

Reactions were carried out at various pressures (15 bar, 35 bar, 50 barand 70 bar), various temperatures (350° C., 360° C., 365° C., 370° C. &380° C.), whsv (0.5 h⁻¹) and various H₂/wax ratios (1000, 1200 and3000). The results obtained after stabilising the reactor for 3-4 daysat given temperature and pressure are shown in table 8.

TABLE 8 The effect of temperature on diesel selectivity and dieselproperties at 35 bar, a H₂/wax ratio of 1200 and whsv of 0.5 h⁻¹ Run R40 R 37 R 38 Pressure (bar) 35 35 35 Temperature (° C.) 350 360 365 WHSV(h⁻¹) 0.5 0.5 0.5 H₂:wax 1215 1238 1302 Conversion (%) 16.6 69.0 86.4Y_(C1-C4) (%) 0.3 0.8 1.8 Y_(C5-C9) (%) 1.6 15.2 21.2 Y_(C10-C22) (%)14.6 53 63.3 Residue (%) 83.4 31 13.6 Diesel/naphtha 8.9 3.5 3.0 DieselProperties iP/nP in C₁₀-C₂₂ 3.3 4.6 5.3 Cloud point (° C.) −9 −18 −17CFPP (° C.) −20 −25 Cetane number 75 71 70

The invention claimed is:
 1. An amorphous hydrocracking catalyst forconversion of at least a portion of a hydrocarbon feed having a fractionabove the diesel boiling range to diesel, said catalyst consistingessentially of: an Al₂O₃—SiO₂support; a noble catalytically active metalwhich is active at least for the hydrocracking of a hydrocarbon abovethe diesel boiling range; and a transition metal oxide wherein thetransition metal is selected from Group V and Group VI transitionmetals; wherein the transition metal oxide is between about 1.5% andabout 12% of the catalyst weight.
 2. A catalyst as claimed in claim 1,wherein the ratio of SiO₂to Al₂O₃in the support is between 1:4 and 4:1.3. A catalyst as claimed in claim 1, wherein the catalytically activenoble metal is present at between 0.1% to 2.0% of the weight of thecatalyst.
 4. A catalyst as claimed in claim 1, wherein the catalyticallyactive noble metal is Pt, Pd, Ir or Rh.
 5. A catalyst as claimed inclaim 4, wherein the catalytically active noble metal is Pt.
 6. Acatalyst as claimed in claim 1, wherein the transition metal oxide is aGroup VI transition metal oxide.
 7. A catalyst as claimed in claim 6,wherein the transition metal oxide is MoO₃.
 8. A catalyst as claimed inclaim 1, wherein the catalyst is a non-sulphided catalyst.
 9. A catalystas claimed in claim 1, wherein the catalyst is an amorphoushydrocracking catalyst for conversion of at least a portion of ahydrocarbon feed having a fraction above the diesel boiling range todiesel, wherein the catalyst is Pt/MoO₃/Al₂O₃SiO₂ having about 1.2 wt%Pt and about 2 wt% MoO₃, and an SiO₂ to Al₂O₃ weight ratio of about 3:1.